3,6-disubstituted pyridazine derivatives

ABSTRACT

A 3,6-disubstituted pyridazine having excellent platelet agglutination inhibitory effects is useful for a preventive or a therapeutic medicine for a cerebrovascular disorder such as cerebral thrombosis and cerebral embolism, an ischemic heart disease such as myocardial infarction, and a circulation disorder such as peripheral circulation disorder. A pharmaceutical composition containing a compound of the present invention and a process for preparing are also disclosed. The compound has the formula (I)    &lt;IMAGE&gt;  (I)  wherein A represents an alkyl having 3 to 6 carbon atoms; a cycloalkyl having 5 to 7 carbon atoms; phenyl, thienyl, furyl, thiazolyl, phenoxy, phenylalkyl having 7 to 9 carbon atoms, phenylthio, a 5-6 membered saturated heterocyclic group containing one or more nitrogen atoms, a pyridyl group or an imidazolyl group each of which may have at least one substituent selected from the group consisting of an alkyl having 1 to 4 carbon atoms, an alkoxy having 1 to 4 carbon atoms and a halogen; B represents (a) -NH-D wherein D represents    &lt;IMAGE&gt;  (1)   &lt;IMAGE&gt;  (2)   &lt;IMAGE&gt; to 8 carbon atoms; or    &lt;IMAGE&gt;  (b)  and the ring C represents a furan ring or a thiophene ring which may be substituted by an alkyl group having 1 to 4 carbon atoms.



